Properties of waves + doppler effect

Longitudinal wave

A wave where the particles vibrate in the same direction as the wave’s motion

Transverse wave

A wave where the particles vibrate at a right angle to the wave’s motion

Examples of longitudinal waves

Sound waves

Ultrasound waves

Vibration of a spring

3 Examples of transverse waves

radio waves

Microwaves

Light waves

What is the equation for a period of a wave (time taken to complete one oscillation (vibration))

Period = 1 / frequency

What is the equation for frequency (number of oscillations per second)

Frequency = 1 / period

What is wavelength?

The distance between a point on one wave and the same point of the next wave

What is amplitude?

The distance from the centre line and the highest / shortest point on a wave

Equation for wave speed?

Wave speed = frequency x wavelength

Define the doppler effect

The apparent change in observed wavelength and frequency of a wave emitted by a moving source relative to an observer

How does the doppler effect work?

Stationary object emits waves symmetrically. To an observer in front, the waves appear to get squashed and frequency appears to get higher. To an observer behind, the waves appear to get stretched and frequency appears to get lower